This is a project to study th energy requirements of nerve for its various functions, and to study in more detail axoplasmic flow, because it uses energy, because different axons are apparently characterized by moving mitochondria with different enzyme complements, and because flow exhibits a specific constellation of responses to injury, namely the formation of what we call a turnabout zat the site of interruption. This turnaround may be the means by which the fact of axonal injury is communicated back to the perikaryon initiating chromatolysis. The rate of energy use will be measured in resting rat nerves with and without blockade, by specific inhibitors, of the Na-K pump and of axonal flow. In addition, the perfused rat hindquarter preparation of the nehrectomized anesthetized rat will be used for a tracer study of the penetration of the non-metabolizable glucose analogue 3-0-methyl glucose into nerve, its kinetics and volume of distribution, to discover whether glucose enters nerve by facilitated transport, and whether penetration of glucose into nerve is affected by such agents as insulin, and experimental diabetes. Our initial finding that mitochondria transported in sympathetic axons differ in their enzyme complement from those in whole rat sciatic nerve will be extended to enquire, using ventral rhizotomy or sensory ganglionectomy, whether mitochondria moving in motor and sensory axons also differ in their enzyme complements. In addition, chemical differences between mitochondria in orthograde and retrograde motion will be sought using mitochondria tracer-lab elled with amino acids and specific sugars. This will require development of a method for isolation of relatively pure motochondria from rat nerve. Finally the response of the nerve to injury will be studied, to discover the chemical nature of the signal for chromatolysis.